Motor-driven shears



C. DUBOIS MOTOR DRIVEN sHEARs Nav. 4, 1930.

Fired Feb. 6, 1956 'mW/f *l l l a Patented Nov. 4, 1930 UNITED STATESPATENT oFFlcEff CHARLES DUBOIS, or TAMS, FRANCE, ASsIGNoR To SOCITINDUSTRIELLE DE 1un-y TRIEL LENTaEraIsE ET DE CONSTRUCTION, or Tenis,FRANCE l MoToR-nRIvEN sHEARS Application led February 6, 1.930,Seria1'No.426,425, and ih France February 28, 192.9.

The present invention relates `to shears capableofcutting metal bars'ofanyrcross section and adapted to be actuated by a motor.`

Shears of this type are already known,-

which are provided with a Clutch; the operator is then compelled topresent to thecutters the bar to be sheared, then to actuate the clutch;thereV are therefore twvo distinct oper- Y ations, resulting in asubstantial loss ottime.

l '1o-In other shears, thev cutters continuously l'T115 ing the bar tobe sheared; the time passed in Waiting for this openingperiod may not be1 considerable, but itcauses axsubs'tantial loss of timewhen it occursagreat number of The present `invention has foran object to avoid theseinconveniences by providingv Shears in which the cutting of the barauto- -Y mati'cally begins asfsoon as the latter is pre-l sented betweenthe cutters, Without the operafmember. t

. For Vthat purpose, theshear's in accordance 'With the invention have,two cutters, one of which is -acutated by a piston engine," and a .25"tor'being 4compelled toactuate anyV control fied. valve gear associatedwith the piston insuch 1 a manner that the driving action of the fluidlasts only as long'as a resistance is'opposed YYYto the advance of thepiston, this having for resultv that 'the latter has .a reciprocatingmovementofverysmall amplitude as long as f ythe .movable ACutter isrunning idly.

l Thead'ustment is such hat the-interval' -`between the fixedcutter'a-nd the cutter thus L receiving a pulsatory movement is thenalter- V natively a little'greater anda little smaller than thethickness of the bar 'to besheared.

:The latter can then' beeas'ilyand instan' taneously inserted betweenthe cutters.`

Thefpulsations cease as soon as the'bar constitutes ari-obstacle to therapid displacei ment of the movable cutter,and the drivingInforderthattheinvention- Vmay be more l clearly understood, tvvo formsof construction of the shears Will now be described, by

Y is inserted in position.

FigQ 1s a cross section made according tov line fI-I of Fig. l. y

Fig. 3 is a horizontal section made according to line III-IH of Fig. l.y

Fig. 4 isasection'similar to'that of Fig. l, Without any bar'beingplaced between lthe Cutters. Fig. 5 is a Section similar to that of Fig.4, the parts occupying a different position. Fig. 6 Shows a second formof 'carrying out the invention.v y f p Fig.V 7 is a cross section madeaccording to line VII-VII of Fig. 6. l

The shears illustrated in Figs. l to 5 essentially comprise a pneumaticor hydraulic press cylinder b havingan inlet orifice d andv an exhaustorifice m, a piston e on Which a fluid 'under pressure acts inVopposition to a spring c,and theI rod fvvhich carries atits end themovable Cutter g. The fixed cutter z' is carried by a screw j passingthrough an abutment c integral With the cylinder. Each cutter is securedon a member g1 kor '711, provided vvith a vertical finger g2 ori? Whichslides in a vgroove c1 of the frameand which prevents it from rotating,although this member g1 or l is mounted in a cylindrical recess orhousing of the piston rod f or of the Screw f j, respectively.

A valve Z mounted in the piston c, .op-

posite the exhaust orificem, isoonnected, to S the piston by a tensionSpring n'.v The orifice m communicates With a tank 0 in which the 'pumpa Sucks the fluid under pressure for compressing it again.

The operation isas follows: The pump ori-constantly and regularly Sendsthe fluid under pressure, through the orifice" d, into the cylinder b,and this fluid pushes the piston e in opposition tothe action of thespring 7c. The pressure exerted by the pump and the strength of thesprings'lc and n are so controlled that, if no barisA inserted betweenthe valve Z is,

"forwardmovement of thepiston e greater than the `pulling forceofthefspring n, so that this valve remains closed, the tension ofthespring n increasing,"the valve is moved away from the orifice m,allowing the fluid under pressure to escape and permitting the spring lato bring back to its starting posi-V los tion the piston'and the valveZwhich again closes the exhaust orifice m. The cycle is thenY riinishedand the reciprocating movement ot jthepiston takes place over again.rThe pressure ofthe fluidandthe forces of both springs la and n aremoreover adjusted in such a manner that the reciprocating movement ofthe piston isvery limited, of the order of twov yand a halfmillimetersto three millimeters,

The position of the cutter relatively to that ofthe cutter fgisadjustedvby means of i, adjustment of the interval ofthe cutter and tothat of the speed of the pulsations,thebar the screw y, so that theirmaximuminterval ness of the bar to be vshea-red. Owing tothis which ispresented between the cutters can be vnearly `instantaneously and veryeasilyV in serted. 1 The' :piston e is then prevented by the bar to besheared ,7L from advancingias rapidly as previously, andthe pressure inthe press cyl- Vsuddenly diminishes-and no longer balancesy inder bincreases with"suiicient rapidity fin orderithat the pull ofthegspring-n, when it 'begins to act, be insuiiicient for overcomingfthe pre'ssure'of the compressing fluid on .the

valve Z, so that the latter remains closed durling the'remainderof thepiston stroke, that is to say until'thebar 71, is completely sheared.

On the contrary, as soon as the bar is sheared, the-pressure of theyfiuid'in the -presscylinder the pulloi' the 'spring @which becomessufficiently strong for Ypulling the valve Z away tromg-itsseat, thiscausing the escape of theY compressing fluid through the orifice m, the

.return ofthe'piston to its initial positionand-` l y1 therecommencement otits,pulsatorymovement until a new bar is insertedbetwen the 'According to-lthefor-Inof construct-iony ofv the shears.illustrated in Fig.:l 6 therspringr n is mounted insuch aimanner thatitacts on the valvehZ by compression, and the helicall spring 7c iskreplaced bya Vshapedspring` pV tending to open and@ to yspace apart theends 'of `thescrew vand-offl-the, rod f,by pressing on these latterkthrough the medium foffmemv.trimming p ignited. vwith Sinatra-@aon inbranches prevent the membersk g, g'l from rotating relativelyto eachother, thus ensuring ing the eventual rotations of the screw jrelatively to the rod fr The operation is obviously vth-einsameV as inthe preceding case.

the parallelism of the cutters notwithstand- In the form of:constructiondescribed, the

tension of the spring ,n directly varies with "the distance betwe'entlrepistonand tire'valve z but it will be `easilyundersto'o'd that it wouldY, be possible, it needbe, to add between the valve and the piston, anymechanical devicesV tension of the spring n.

Claims z i 1;'Shears'actuatedbya -drivingffluid i der pressure Landadapted to shear members Vofl a definite width,7cornpri'sing ia?cylinder t *havin'gan inlet orifice and anv 'exhaustfforif'ce,L vbe twomillimeters lgreater `than/ they thicka'piston inthis cylinder,fa`fixed'cutter,'a movf able 'cutter actuated the said piston, a n valveonft-he exhaust orifice and openingf'inwardly ofthe f'cylinder, aspri-ngadapted to e 1 canalso be provided formodifying thefiniti'al *I andsufli'clently-rapid in orderthat thekplsf 1 ton may be considered asreceiving a series of pulsations; y

Vclose rthe'said valve,V the" saidspringf'being advancesl 'in'thedirectioncorrespondingf to i to move the pistonin the reverse direction,

' and meansV- ffor continuously delivering the f driving rfluid into'thefjcylinder th'roughiithe said inlet'orifc'e: l Y t ,i

2. Shears actuated by?A a driving fluid under. pressure and adapted-ite"`shear :members f of a' definite width, 'comprising a cylinder having aninlet orifice and an exhaust oriythe closing` oft-the shears, a springfadapted krflou tice, a piston in'thiscylinder, a iixd'cutter, t

a movable .cutter actuatedbythe*saidpiston, f

a valvef on? the exhaust orifice and 'l opening inwardly of thecylindercafspring adapted?y gno to close the said. valve,'the I"saidspringcbeing connected tothe Apistonsofas" to. beprogresthe said Yspringassoon as theY pist'onfh'as moved forward a few-millimetersonly. l

3. Shears actuated byadriving. fluid under??? lpressure and. adaptedto'shear members :of a

'definite width, comprising; a cylinder having n aan* inletoritcefand-an exhaust orifice, avpiston" 1n this cyhnder, a fixedcutter, agp-movable- -cutter actu-ated -A-byqther said piston,fa 1,.val-vewllao on the exhaust orice and opening inwardly of the cylinder,a spring adapted to close the said valve, the said spring beingconnected to the piston so as to be progressively stretched inproportion as the piston moves in the direction corresponding to theclosing of the shears, means for moving the piston in the reversedirection, and means for continuously delivering the driving Huid intothe cylinder through the said inlet orifice, the said spring being suchthat the thrust lof the valve on the exhaust orifice under the pressureof the driving fluid, when the shears operate idly, be overcome by thetension of the said spring when the distance between the cutters is lessthan the width of the parts or members to be cut.

4. Shears actuated by a driving fluid, com-y prising a cylinder havingan inlet orifice and an exhaust orifice, a piston in this cylinder, afixed cutter the position of which is adjustable, a movable cutterrigidly connected to the piston, a valve on the exhaust orifice andopening inwardly of the cylinder, a spring adapted to close the saidvalve, one end of this spring being attached to the s aid valve, and theother end being attached to the said piston, means for moving the pistonin the direction corresponding to the opening of the shears, and meansfor continuously delivering the driving fluid into the cylinder.

In testimony whereof I have hereunto affixed my signature.

' CHARLES DUBOIS.

